In the past seven years methodology for evaluating hemodynamics and ventricular function has been applied to patients with acute myocardial infarction and the feasibility of these studies established. After eliminating hypovolemia and the effects of arrhythmia remaining mortality is related to the extent of myocardial damage. Pressor agents have been helpful in stabilizing the hemodynamic derangement but long term survival remains poor and survivors retain severe cardiac dysfunction. Two methods of reducing infarct size have been suggested: intra-aortic balloon counterpulsation and surgical myocardial revascularization with or without infarctectomy. These procedures deserve critical evaluation and comparison with standard methods of therapy. For this purpose we intend to classify patients with myocardial infarction by hemodynamics and ventricular function during their acute episode. We will follow these patients and periodically test their functional capacity as well as measuring ventricular function after recovery. In this manner the effects of therapy on long term survival and function should become apparent. The effects of bundle branch block and heart block on survival and symptoms will be studied after study of conduction system by His electrograms. Correlation of vectorcardiographic changes with anatomical studies will continue. Criteria derived from data developed in the acute studies will be tested for value in predicting long term survival and function. Sophisticated methods will be correlated with more generally available techniques such as systolic time intervals and central arterial pressure pulse analysis and echocardiography. Studies of septic shock will also continue with studies of acute bacteremia in man. These investigations will include study of the coagulation system, complement and rheumatoid factor, the Kallikrein system and identification of endotoxin in the blood.